Have you shot it, or waiting for range time? I was going to get into that and things just didn't work out. It seemed, at the time, that there was really only two ways to "use" one - either sleeve it to .50 BMG or pay through the nose for Russian .50. What are you going to do?

I have fired about 35 rounds here at the house thru it with an m2 bbl .
The middle bbl in the pic above is an m2 bbl I turned down , the pic right below it is the gas block and gastube support. I machined a sleeve to fit OVER the turned down portion of th m2 bbl with a key at the top for the bbl wedge to contact. The sleeve is screwed in place over the m2 bbl and with the new gas block and support the dshk gas tube fits right in place and the new bbl assembly slides right in place of the original bbl. Didnt modify the original bbl at all and can interchange at will. Using the m2 donor bbl with the adapter sleeve in place has worked well, no sleeve to slip. I do miss the look of the finned bbl.